T1 - Synthesis of Mn-doped zinc blende CdSe nanocrystals
T1 - Synthesis of CdSe quantum dots
Synthesis of nanoparticles of cadmium selenide (CdSe) was carried out using solvothermal method with cadmium nitrate and sodium selenite as precursors. Hydrazine hydrate and ethylenediamine tetra acetic acid were used as the capping agent to control the size of the nanoparticles. As their size decreases to their Bohr radius (usually around a few nanometers), all electronic properties change, and equally important, become dependent on size. In this size, a semiconductor nanoparticle transition occurs in which the electrons and holes are confined beyond their natural Bohr radius. The properties become dependent not only on size, but also on shape. The crystalline nature and particle size of the samples were characterized by Powder X-ray diffraction analysis (XRD). The morphology of prepared CdSe nanoparticles was studied by scanning electron microscope. Dielectric studies were carried out for the pelletized sample of CdSe nanoparticles. The ac conductivity of CdSe nanoparticle has been studied. The obtained results are discussed.
Synthesis of CdSe quantum dots decorated SnO2 …
The semiconductor nanoparticles belong to the state of matter in transition between molecules and bulk solids in which the relevant physical dimensions changes on the length of a few to a few hundred nanometers. Both equilibrium and dynamic properties of nanomaterials can be very different from those of their corresponding bulk materials or isolated atoms and molecules. The dielectric constant of a semiconductor is one among its most important properties. Its magnitude and temperature dependence are significant in both fundamental and technological considerations. Recently, many extensive studies are going on in the semiconductor nanocrystals because they exhibit strong size dependent optical properties. These will be the key structural parameters in the fabrication of novel electronic nanodevices and nanocircuits. Semiconductor particles exhibit size dependent properties such as the scaling of the energy gap and corresponding change in the optical properties. CdSe is one of such materials, shows strong fluorescence which can be tuned according to the particle size. CdSe has been considered in many applications such as optoelectronic devices (Nazzal et al. ), light sensors (Bruchez et al. ), biological labels (Colvin et al. ), chemical libraries (Gaponik et al. ), etc. The nanopowder of CdSe provides excellent and unique properties which depend upon the shape and size of the nanostructures (Haram et al. ; Wang et al. ; Datta and Das ; Peng et al. ). Various methods such as hydrothermal, sol–gel approach, surfactant-assisted approach, etc. had been utilized for the synthesis of nanoparticles (Tang et al. ; Busbee et al. ). Synthesis, structural, and optical properties of CdSe nanoparticles have been reported (Dwivedi et al. ). In the present study, the main focus is on the electrical properties of pellets of nanoparticles of CdSe at different temperatures. The frequency dependence of dielectric constant, dielectric loss and ac conductivity was also investigated.